From: Zi Yan <ziy@xxxxxxxxxx> Subject: mm/migrate: correct thp migration stats PageTransHuge returns true for both thp and hugetlb, so thp stats was counting both thp and hugetlb migrations. Exclude hugetlb migration by setting is_thp variable right. Clean up thp handling code too when we are there. Link: https://lkml.kernel.org/r/20200917210413.1462975-1-zi.yan@xxxxxxxx Fixes: 1a5bae25e3cf ("mm/vmstat: add events for THP migration without split") Signed-off-by: Zi Yan <ziy@xxxxxxxxxx> Reviewed-by: Daniel Jordan <daniel.m.jordan@xxxxxxxxxx> Cc: Anshuman Khandual <anshuman.khandual@xxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/migrate.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) --- a/mm/migrate.c~mm-migrate-correct-thp-migration-stats +++ a/mm/migrate.c @@ -1446,7 +1446,7 @@ retry: * Capture required information that might get lost * during migration. */ - is_thp = PageTransHuge(page); + is_thp = PageTransHuge(page) && !PageHuge(page); nr_subpages = thp_nr_pages(page); cond_resched(); @@ -1472,7 +1472,7 @@ retry: * we encounter them after the rest of the list * is processed. */ - if (PageTransHuge(page) && !PageHuge(page)) { + if (is_thp) { lock_page(page); rc = split_huge_page_to_list(page, from); unlock_page(page); @@ -1481,8 +1481,7 @@ retry: nr_thp_split++; goto retry; } - } - if (is_thp) { + nr_thp_failed++; nr_failed += nr_subpages; goto out; _
